1. Technical Field
This invention relates to a vehicle navigation system that displays views of intersections. In particular, the invention relates to a navigation system that provides an animated view of upcoming intersections.
2. Related Art
Navigation systems are increasingly prevalent in vehicles. A navigation system analyzes position data provided by Global Positioning System (GPS) satellites and received by an on-board GPS sensor. The navigation system may also analyze position or motion data obtained from other sources, including motion sensors and digital maps, to determine the position and velocity of the vehicle.
The navigation system displays a detailed digital map for the driver. In addition to the vehicle location, the map may include cartographic features, such as streets, buildings, rivers, gas stations, restaurants, landmarks and other points of interest. A compact disk or digital video disk may store the cartographic data for display on the map.
The navigation system may also display routes to destinations and the maneuvers (e.g., turns or merges) needed to reach the destination. As the vehicle changes position, a vehicle position mark on the map changes to reflect the updated vehicle position. Alternatively, the digital map may be scrolled, while the vehicle position mark may be fixed at a predetermined position.
To help the driver identify the proper route, some navigation systems provide enlarged views of intersections where the driver should turn in order to reach the destination. Other navigation systems provide three-dimensional perspective views of the intersections. In some systems, the map displays the intersection approached by the vehicle at an angle which varies depending on the complexity of the intersection.
However, in such systems, the complexity of the road geometry in the forward path of the vehicle may cause orientation difficulties for the driver. For both two- and three-dimensional representations, it may be difficult for the driver to keep proper orientation and the driver may become confused by the displayed digital map. Driver confusion may increase with increasing complexity of the intersections, particularly when roads intersect at different height levels or run in rotary turns with other roads in close proximity. In addition, when the navigation system provides a driver with an enlarged perspective view of the intersection from a standpoint which differs from the actual position of the vehicle, the driver may need time to become properly oriented. The time consumed by the orientation process may lead to missed turns, increased travel time, and other undesirable results.
Therefore, a need exists for a vehicle navigation system which provides improved visualization of upcoming intersections.